<script type="text/javascript">   
    function changeValidateCode() {   
        var timenow = new Date().getTime();      
        $("#randImg").attr("src","${base}/random!execute?id="+timenow);   
    }   
</script> 
		<em>
		<a href="javascript:changeValidateCode()" hidefocus title="换一张">
			<img id="randImg" src="${base}/random!execute"  border="0" style="margin-top:10px; float:left; margin-right:10px;" />
		</a>
		</em>